The Journal of Organic Chemistry
FEATURED ARTICLE
N-Phenyl-N0-(2-vinylbenzylidene)hydrazine 5i. According to general
procedure B, 5i was obtained from aldehyde 4a (663 mg, 5.0 mmol) and
phenylhydrazine (542 mg, 5.0 mmol) as a light yellow oil: 1.09 g (98%,
4.9 mmol) yield; IR (neat) ν~ = 3306, 3055, 3026, 2911, 1661, 1601,
1495, 1447, 1314, 1258, 1246, 1128, 1069, 1036, 883, 750, 694, 633; 1H
NMR (400 MHz, CDCl3) δ 5.37 (dd, J = 11.0, 1.4 Hz, 1H), 5.61 (dd, J =
17.4, 1.4 Hz, 1H), 6.86 (tt, J = 7.4, 1.1, 1H), 7.09 (m, 2H), 7.16 (dd, J =
17.4, 11.0 Hz, 1H), 7.21-7.31 (m, 4H), 7.41-7.47 (m, 1H), 7.63 (s,
1H), 7.84-7.89 (m, 1H), 7.91 (s, 1H); 13C NMR (101 MHz, CDCl3) δ
112.7, 117.0, 120.1, 126.4, 126.9, 127.8, 128.3, 129.2, 129.3, 132.2, 134.6,
135.4, 136.3, 144.6; HRMS (ESI) calcd for C15H14N2Na 223.1230,
found 223.1237.
J = 8.0, 1.2, 0.7, 1H), 7.65 (s, 1H), 8.94 (ddd, J = 8.2, 1.2, 0.7, 1H); 13
C
NMR (75 MHz, C6D6) δ 18.8, 34.9, 122.0, 123.8, 124.9, 125.3, 126.0,
127.3, 129.4, 130.3, 138.2, 139.3, 139.9; HRMS (ESI) calcd for
C13H15N2S 231.0950, found 231.0951.
Synthesis of 4,5-Dihydro-3H-benzo[d][1,2]diazepines
6a-d. General procedure C for the deprotonation and further
conversion of hydrazones 5a-n was performed. To a solution of 2
mmol of hydrazone in 30 mL of abs THF, 1.5 equiv (3.0 mL, 3.0 mmol)
of KO-t-Bu (1 M in THF) was added at room temperature. The solution
was stirred for 16 h and was quenched subsequently with saturated
NH4Cl solution. After dilution with TBME, the mixture was washed with
brine, dried over MgSO4, filtered, and concentrated.
N-Phenyl-N0-(2-((E/Z)-prop-1-enyl)benzylidene)hydrazine 5j. Ac-
cording to general procedure B, 5j was obtained from aldehyde 4c
(730 mg, 5.0 mmol) and phenylhydrazine (540 mg, 5.0 mmol) as an
orange resin: 968 mg (82%, 4.1 mmol) with an E/Z ratio of 2/1; bp
153 °C/8.0 ꢀ 10-2 mbar; IR (neat) ν~ = 3314, 3028, 2963, 2909, 1694,
1599, 1576, 1557, 1520, 1493, 1443, 1373, 1308, 1288, 1260, 1192, 1171,
1138, 1105, 1069, 993, 964, 945, 914, 881, 748, 691, 669, 650, 640, 615;
1H NMR (300 MHz, C6D6) δ 1.56 (dd, J = 7.0, 1.8 Hz, 3H, Z), 1.76 (dd,
J = 6.6, 1.8 Hz, 3H, E), 2.71 (s, 1H, Z), 4.44 (s, 1H, E), 5.75 (dq, J = 11.4,
7.0 Hz, 1H, Z), 5.90 (dq, J = 15.5, 6.6 Hz, 1H, E), 6.48-6.51 (m, 1H, E),
6.51-6.54 (m, 1H, Z), 6.56 (q, J = 1.8, 1H, E), 6.71-6.91 (m, 2H, E, 2H,
Z), 6.98-7.19 (m, 6H, Z, 6H, E), 7.19-7.29 (m, 2H, Z, 1H, E), 7.34 (s,
1H, E), 7.36 (s, 1H, Z), 8.06 (m, 1H, E), 8.17-8.26 (m, 1H, Z); 13C
NMR (75 MHz, CDCl3) δ 13.0, 17.5, 111.00, 111.7, 117.8, 118.9, 124.3,
124.4, 125.2, 125.9, 125.9, 126.1, 126.5, 126.9, 127.0, 127.1, 127.3, 127.8,
127.9, 127.9, 128.2, 128.2, 128.6, 132.4, 134.2, 134.4, 134.4, 135.3;
HRMS (ESI) C16H16N2Na calcd for 259.1206, found 259.1212.
N-(4-Fluorophenyl)-N0-(2-vinylbenzylidene)hydrazine 5l. Accord-
ing to general procedure B, 5l was obtained from aldehyde 4a (658
mg, 5.0 mmol) and 4-fluorophenylhydrazine (629 mg, 5.0 mmol) as a
yellow resin: 1.15 g (62%, 3.1 mmol); IR (neat) ν~ = 3237, 3067, 2963,
1684, 1653, 1601, 1506, 1300, 1260, 1223, 1153, 1076, 1013, 918, 862,
797, 772, 689, 662, 648, 604; 1H NMR (400 MHz, CDCl3) δ 5.38 (dd,
J = 11.0, 1.4 Hz, 1H), 5.62 (dd, J = 17.4, 1.4 Hz, 1H), 6.90-7.06 (m,
4H), 7.15 (dd, J = 17.4, 11.0, 1H), 7.24-7.32 (m, 2H), 7.41-7.47 (m,
1H), 7.59 (s, 1H), 7.82-7.88 (m, 1H), 7.94 (s, 1H); 13C NMR
(101 MHz, CDCl3) δ 113.7 (d, 7.5 Hz), 115.5 (d, J = 22.6 Hz), 117.1
126.3, 126.9, 27.8, 128.4, 132.1, 134.5, 135.6, 136.3, 141.0 (d, J = 2.1 Hz),
157.3 (d, J = 237.0 Hz); HRMS (ESI) calcd for C15H13FN2Na 263.0955,
found 263.0962.
3-Methyl-4,5-dihydro-3H-benzo[d][1,2]diazepine 6a. According
to general procedure C after deprotonation of hydrazone 5a (321 mg,
2.0 mmol) and purification by HPLC (n-pentane 85%, TBME 10%, TEA
5%), 6a was obtained as a colorless oil: 232 mg (71%, 1.4 mmol); bp of
115 °C/1 ꢀ 10-3 mbar; IR (neat) ν~ = 3061, 3017, 2955, 2909, 2855,
2791, 1558, 1495, 1445, 1400, 1310, 1258, 1204, 1150, 1117, 1022, 924,
874, 781, 756, 727, 698, 664, 633, 611; 1H NMR (300 MHz, C6D6) δ
2.79-2.85 (m, 2H), 2.92 (ddd, J = 5.6, 3.7, 1.1, 2H), 2.95 (s, 3H), 6.80-
6.85 (m, 1H), 6.92 (dd, J = 7.2, 2.0, 1H), 6.95-6.99 (m, 1H), 7.00-7.04
(m, 1H), 7.27 (s, 1H); 13C NMR (101 MHz, CDCl3) δ 37.8, 48.4, 54.2,
126.4, 127.6, 129.2, 132.2, 132.5, 135.3, 139.8; HRMS (ESI) calcd for
C10H13N2 161.1073, found 161.1075. Anal. Calcd for C10H12N2
(160.22): C, 74.97; H, 7.55; N,17.48. Found: C, 75.14; H, 7.80; N, 17.26.
3,5-Dimethyl-4,5-dihydro-3H-benzo[d][1,2]diazepine 6b. Accord-
ing to general procedure C after deprotonation of hydrazone 5b (349
mg, 2.0 mmol) and purification by column chromatography (n-pentane
85%, TBME 10%, TEA 5%), 6b was obtained as a colorless oil: 317 mg
(91%, 1.82 mmol); IR (neat) ν~ = 3061, 3005, 2959, 2856, 1558, 1491,
1462, 1439, 1402, 1368, 1323, 1254, 1240, 1211, 1153, 1090, 1078, 1036,
1
997, 907, 808, 754, 698, 658, 633, 588, 549; H NMR (300 MHz,
CDCl3) δ 1.24-1.29 (m, 3H), 3.15 (d, J = 12.5, 1H), 3.21 (s, 3H), 3.29
(ddd, J = 17.6, 12.7, 5.9 Hz, 2H), 7.07 (s, 1H), 7.12-7.30 (m, 4H); 13C
NMR (75 MHz, CDCl3) δ 22.3, 41.7, 49.0, 58.6, 126.3, 127.2, 128.7,
131.7, 132.2, 133.9, 145.2; HRMS (ESI) calcd for C11H15N2 175.1230,
found 175.1232. Anal. Calcd for C11H14N2 (174.24): C, 75.82; H, 8.10;
N, 16.08. Found: C, 75.82; H, 8.20; N, 16.05.
3,4-Dimethyl-4,5-dihydro-3H-benzo[d][1,2]diazepine 6c. According
to general procedure C after deprotonation of hydrazone 5c (346 mg,
2.0 mmol) and purification by Kugelrohr distillation (143 °C/2 ꢀ 10-
2 mbar), 6c was obtained as a colorless oil: 264 mg (75%, 1.5 mmol); IR
(neat) ~ν = 3060, 3016, 2974, 2929, 2868, 2806, 1583, 1556, 1492, 1444,
1400, 1375, 1350, 1319, 1263, 1251, 1205, 1157, 1124, 1109, 1072, 1026,
993, 947, 914, 879, 848, 804, 756, 730, 690, 667; 1H NMR (400 MHz,
CDCl3) δ 0.92 (d, J = 6.8 Hz, 3H). 2.94 (dd, J = 15.8, 5.6 Hz, 1H), 3.19 (s,
3H), 3.31 (d, J = 15.8 Hz, 1H), 3.86-3.94 (m, 1H), 7.07-7.26 (m, 5H);
13C NMR (101 MHz, CDCl3) δ 12.3, 42.7, 46.3, 56.7, 126.4, 127.4, 129.9,
130.5, 132.3, 133.9, 136.6; HRMS (ESI) calcd for C11H15N2 175.1235,
found175.1237. Anal. CalcdforC11H14N2 (174.24): C, 75.82; H, 8.10; N,
16.08. Found: C, 75.57; H, 8.14; N, 16.13.
3,4-Dimethyl-4,5-dihydro-3H-thiopheno[d][1,2]diazepine 6d. Ac-
cording to general procedure C after deprotonation of hydrazone 5n
(463 mg, 2.0 mmol) and purification by column chromatography (cyclo-
hexane 90%, TBME 10%), 6d was obtained as a colorless solid: 142 mg
(31%, 0.62 mmol); mp 75-78 °C; IR (neat) ~ν = 2984, 2916, 2872, 2799,
1558, 1535, 1460, 1449, 1437, 1395, 1377, 1350, 1319, 1240, 1177, 1155,
1111, 970, 945, 901, 868, 785, 752, 729, 675, 650, 606; 1H NMR
(300 MHz, C6D6) δ 0.88-0.70 (m, 3H); 2.64 (td, J = 4.9, 1.5, 1H), 3.03
(d, J = 4.9, 3H), 3.32-3.04 (m, 2H), 7.12-6.95 (m, 2H), 7.50-7.41 (m,
1H), 7.62-7.52 (m, 1H), 7.81 (s, 1H); 13C NMR (75 MHz, C6D6) δ
10.5, 38.1, 47.5, 55.7, 121.2, 122.2, 124.5, 124.8, 127.2, 127.3, 139.3,
139.7, 140.3; HRMS (ESI) calcd for C13H15N2S 231.0950, found
N-(4-Fluorophenyl)-N0-(2-β-styrylbenzylidene)hydrazine 5m. Ac-
cording to general procedure B, after recrystallization from ethanol
5m was obtained from aldehyde 4d (1.03 g, 5.0 mmol) and 4-fluor-
ophenylhydrazine (633 mg, 5.0 mmol) as a yellow solid: 0.59 g (37%, 1.9
mmol); mp 143 °C (ethanol); IR (neat) ν~ = 3291, 3048, 3022, 1595,
1553, 1510, 1493, 1479, 1447, 1416, 1354, 1290, 1256, 1209 (s, CF),
1152, 1126, 1088, 1074, 1045, 964, 916, 827, 802, 752, 729, 691, 652,
1
602; H NMR (400 MHz, CDCl3) δ 6.89-6.96 (m, 3H), 6.97-7.03
(m, 3H), 7.26-7.33 (m, 3H), 7.34-7.40 (m, 2H), 7.55 (m, 3H), 7.64
(d, J = 16.1, 1H), 7.74-7.79 (m, 1H), 7.98 (s, 1H); 13C NMR
(101 MHz, CDCl3) δ 113.7 (d, J = 7.5 Hz), 115.8 (d, J = 22.6 Hz),
126.7, 126.9, 127.1, 127.3, 127.7, 127.8, 128.4, 128.8, 131.4, 132.4, 135.9,
136.2, 137.5, 140.9 (d, J = 2.2 Hz,), 157.3 (d, J = 237.4 Hz); HRMS (ESI)
calcd for C21H17FN2Na 339.1268, found 339.1273.
1-Methyl-2-((2-prop-1-enyl)benzo[b]thiophen-3-yl)methylene)hyd-
razine 5n. According to general procedure B, 5n was obtained from
aldehyde 4i (1.01 g, 5.0 mmol) and methylhydrazine (345 mg, 7.5 mmol)
as a light yellow oil: 1.07 g (93%, 4.7 mmol); IR (neat) ~ν = 3393, 3316,
2963, 2909, 2868, 1589, 1458, 1433, 1369, 1200, 1155, 1121, 1080, 1018,
943, 758, 731; 1H NMR (300 MHz, C6D6) δ 1.62 (dd, J = 6.8, 1.8, 3H),
2.53 (d, J = 0.5, 3H), 6.13 (dq, J = 15.4, 6.7, 1H), 6.91 (dq, J = 15.4, 1.7,
1H), 7.14-7.06 (m, 1H), 7.29 (ddd, J = 8.3, 7.1, 1.2, 1H), 7.52 (ddd,
1988
dx.doi.org/10.1021/jo2001534 |J. Org. Chem. 2011, 76, 1979–1991